Return to the CurtPalme.com main site CurtPalme.com Home Theater Forum
A forum with a sense of fun and community for Home Theater enthusiasts!
Products for Sale ] [ FAQ: Hooking it all up ] [ CRT Primer/FAQ ] [ Best/Worst CRT Projectors List ] [ Setup Tips & Manuals ] [ Advanced Procedures ] [ Newsletters ]

 
Forum FAQForum FAQ   SearchSearch   MemberlistMemberlist  Photo AlbumsPhoto Albums  RegisterRegister 
 MembershipClub Membership   ProfileProfile   Private MessagesPrivate Messages   Log inLog in 
Blu-ray disc release list and must-have titles. Buy the latest and best Blu-ray titles to show off in your home theater!

Screen cap vs crt camera thread
Goto page Previous  1, 2
 
Post new topic   Reply to topic   Printer-friendly view    CurtPalme.com Forum Index -> CRT Projectors
View previous topic :: View next topic  
Author Message
mp20748




Joined: 12 Sep 2006
Posts: 5681
Location: Maryland

TV/Projector: 9500LC Ultra / Super 02 and 03 VIM


PostLink    Posted: Sun May 28, 2017 7:46 pm    Post subject: Reply with quote


        Register to remove this ad. It's free!
racerxnet wrote:
Taking a screen cap and comparing it to your image on screen can help see if details are present or not. Making A DISPLAY LOOK ITS BEST REQUIRES A CALIBRATION. PERIOD. This has been explained by Kal as well. If your calibration is not done then the colors are also an impediment to judging your mods.
MAK


Let me revisit this part (above) right here. After going over to that other forum, and base on what I have put in bold above, and since you know where that is. Can you explain to me why Greg's shots look the way they do, when as he said they both have the same boards and their projectors are calibrated....now when Greg posted that shot from Oblivion on this forum yesterday, I was stoked as to what it look like. As I've looked at most of his shots, they looked just like I would expect, considering the video chain. And I say that because of a conversation in email with him some days ago. There was something he posted in that email, I won';t post here, but it has me thinking and wondering why his setup looks so different from the other one over there and they are mirrors of each other in everything to include the calibration.

Why if both are the same in everything, one looks so much different from the other?


Greg's shots look like they are from a stock set that needs calibration. There is zero sharpness, zero depth and they are noisy. Am I the only one seeing this?


And for sure, I will be calibrating some time soon..Mr. Green
Back to top
mp20748




Joined: 12 Sep 2006
Posts: 5681
Location: Maryland

TV/Projector: 9500LC Ultra / Super 02 and 03 VIM


PostLink    Posted: Sun May 28, 2017 8:52 pm    Post subject: Reply with quote

The one on the top is my shot. The one below that I'd rather not resize is a screencap.

This is my best camera, and this is also totally before any calibration or serious focusing. I'll just put this right here for now. And from now on until I get things calibrated, I'll use my best camera.

Also, there is ZERO , none enhancements. just a super video chain in action..Mr. Green





apocalypto-movie-screencaps.com-5929.jpg
 Description:
 Filesize:  320.89 KB
 Viewed:  3829 Time(s)

apocalypto-movie-screencaps.com-5929.jpg


Back to top
El Duderino




Joined: 23 Jan 2011
Posts: 4627
Location: Portland, OR


PostLink    Posted: Sun May 28, 2017 9:24 pm    Post subject: Reply with quote

mp20748 wrote:
El Duderino wrote:
The image information on a BD is encoded in YCbCr format


Is this information "pure, and unadulterated" as what you indicated about the Screencap (Frame buffered capture). Are both lossless (no compression). We know there could be mpeg2, mpeg4, VC-1, etc. for the length of the movies we're familiar with.


Quote:
Most displays use an RGB format so there is a necessary mathematical transcode from YCbCr space to RGB space. If we are going to examine, contrast or compare images on an internet based forum like curtpalme.com using a base HTML browser, then the images will be 8-bit RGB based (sRGB) no matter if the source was BD, DVD, or from a camera pointed at a screen as 8-bit sRGB is the default color space for the internet presentl


I follow this point, but still need to distinguish where we are with Blu Ray and Frame Capture. Are they the same source?.


Yes and no. You can't post the native YCbCr that is encoded on the disk to the internet as images in a web browser expect and use sRGB format. The BD source information is in YCbCr space and what is in a frame buffer has been transcoded to RGB space.
Back to top
mp20748




Joined: 12 Sep 2006
Posts: 5681
Location: Maryland

TV/Projector: 9500LC Ultra / Super 02 and 03 VIM


PostLink    Posted: Sun May 28, 2017 9:33 pm    Post subject: Reply with quote

El Duderino wrote:
mp20748 wrote:
El Duderino wrote:
The image information on a BD is encoded in YCbCr format


Is this information "pure, and unadulterated" as what you indicated about the Screencap (Frame buffered capture). Are both lossless (no compression). We know there could be mpeg2, mpeg4, VC-1, etc. for the length of the movies we're familiar with.


Quote:
Most displays use an RGB format so there is a necessary mathematical transcode from YCbCr space to RGB space. If we are going to examine, contrast or compare images on an internet based forum like curtpalme.com using a base HTML browser, then the images will be 8-bit RGB based (sRGB) no matter if the source was BD, DVD, or from a camera pointed at a screen as 8-bit sRGB is the default color space for the internet presentl


I follow this point, but still need to distinguish where we are with Blu Ray and Frame Capture. Are they the same source?.


Yes and no. You can't post the native YCbCr that is encoded on the disk to the internet as images in a web browser expect and use sRGB format. The BD source information is in YCbCr space and what is in a frame buffer has been transcoded to RGB space.



I'm not following this. I was asking if what is the difference between the two. If Frame capture is pure and unadulterated, what is going on on a Blu Ray, it it compressed because of the codacs it uses.

My second question was, were you indicating that both Blu Ray and Frame capture came from the same source.


Also and above I've posted a shot from my screen and below it a raw from the internet screencap of the same image. In those two, you'll see what I was saying about the colors, though not calibrated, the CRT is more color saturated.
Back to top
El Duderino




Joined: 23 Jan 2011
Posts: 4627
Location: Portland, OR


PostLink    Posted: Sun May 28, 2017 9:36 pm    Post subject: Reply with quote

mp20748 wrote:
Also, there is ZERO , none enhancements. just a super video chain in action..Mr. Green

Not too shabby. If I'm hyper critical, it looks like your blacks are a bit crushed. Of course, this could all be in the camera. Note the wisp of hair above the ear on the right hand side of the reference image or the area where the ear adornment stands out from the face on the left hand side. I can't resolve these details on your shot on my monitor.

mp20748 wrote:
I'm not following this. I was asking if what is the difference between the two. If Frame capture is pure and unadulterated, what is going on on a Blu Ray, it it compressed because of the codacs it uses.

My second question was, were you indicating that both Blu Ray and Frame capture came from the same source.

Again, what is in the frame buffer in RGB color space was computed from the YCbCr information encoded on the BD. It's the same 'source' information but they are necessarily in different color spaces. You can't post a YCbCr encoded image that we can observe with a base web browser. It HAS to be transcoded to RGB color space and if for it to be correct it has to be specifically sRGB color space.

mp20748 wrote:
In those two, you'll see what I was saying about the colors, though not calibrated, the CRT is more color saturated.

Agreed. If one says the frame buffer grab most represents 'accurate' or is most representative of the image information encoded on the BD, then your shot appears a bit over saturated with a bit of black crush in comparison to me. Also note the color of the background above the shoulder. Your shot has it at a higher color temp (more bluish) to my eyes but not too shabby considering there is a camera and screen involved. My comments are hyper-critical, but when images are posted in an A/B manner one can be that way. FWIW, most of your shots strike me as bit over saturated even when not done in an A/B manner.
Back to top
mp20748




Joined: 12 Sep 2006
Posts: 5681
Location: Maryland

TV/Projector: 9500LC Ultra / Super 02 and 03 VIM


PostLink    Posted: Sun May 28, 2017 10:38 pm    Post subject: Reply with quote

El Duderino wrote:
Not too shabby. If I'm hyper critical, it looks like your blacks are a bit crushed. Of course, this could all be in the camera. Note the wisp of hair above the ear on the right hand side of the reference image or the area where the ear adornment stands out from the face on the left hand side. I can't resolve these details on your shot on my monitor


Yes, the camera surely limits the IRE window when doing this, it just does not have the dynamics. That plus things have not yet been calibrated and that would also cover the hair, because focus has a long ways to go. fact is, after installing the GREEN tube, I only focused the center. None of the stig has been done globally.


Quote:
Again, what is in the frame buffer in RGB color space was computed from the YCbCr information encoded on the BD. It's the same 'source' information but they are necessarily in different color spaces. You can't post a YCbCr encoded image that we can observe with a base web browser. It HAS to be transcoded to RGB color space and if for it to be correct it has to be specifically sRGB color space


We're not understanding here. I only want to know if the Blu Ray and Frame Grab (is another word for it) are the same or is one or both doing any compressing.


Agreed. If one says the frame buffer grab most represents 'accurate' or is most representative of the image information encoded on the BD, then your shot appears a bit over saturated with a bit of black crush in comparison to me. Also note the color of the background above the shoulder. Your shot has it at a higher color temp (more bluish) to my eyes but not too shabby considering there is a camera and screen involved. My comments are hyper-critical, but when images are posted in an A/B manner one can be that way. FWIW, most of your shots strike me as bit over saturated even when not done in an A/B manner.[/quote]

The over saturation has to be corrected using a processor or other ability to decrease the saturation. The Grabs will also look like this in comparison to the Frame Grabs.


My setup is in serious need of calibration and finer tuning. I'm pleased that you've not mentioned sharpness being a problem, which would not be the case with this video chain at all. And if you knew how much better it could get after things are dialed in better, there's a lot more to expect from this setup. Surely the need for a Darby of other sharpening tweak, will never be needed or desired.

I posted the comparison to give an idea of how well things will look even when everything is not where it should be. This video chain is the BEAST. And I'm going to let that beast out the cage after I get things dialed in the way they should be..: Mr. Green
Back to top
El Duderino




Joined: 23 Jan 2011
Posts: 4627
Location: Portland, OR


PostLink    Posted: Sun May 28, 2017 11:13 pm    Post subject: Reply with quote

mp20748 wrote:
We're not understanding here. I only want to know if the Blu Ray and Frame Grab (is another word for it) are the same or is one or both doing any compressing.


The YCbCr on the BD had lossy compression applied during the mastering for consumer release. Nothing that happens after that (transcoding from the YCbCr on the disk into RGB in the frame buffer) can 'undo' that loss. The image in the frame buffer captured in RGB color space is as close to what is encoded on the BD as you can post to the internet. Ideally it shouldn't be further compressed, but in practice frame grabs are often posted in lossy .jpeg format. The better frame buffer grabs will be posted in a lossless format like .png.
Back to top
mp20748




Joined: 12 Sep 2006
Posts: 5681
Location: Maryland

TV/Projector: 9500LC Ultra / Super 02 and 03 VIM


PostLink    Posted: Sun May 28, 2017 11:26 pm    Post subject: Reply with quote

El Duderino wrote:
mp20748 wrote:
We're not understanding here. I only want to know if the Blu Ray and Frame Grab (is another word for it) are the same or is one or both doing any compressing.


The YCbCr on the BD had lossy compression applied during the mastering for consumer release. Nothing that happens after that (transcoding from the YCbCr on the disk into RGB in the frame buffer) can 'undo' that loss. The image in the frame buffer captured in RGB color space is as close to what is encoded on the BD as you can post to the internet. Ideally it shouldn't be further compressed, but in practice frame grabs are often posted in lossy .jpeg format. The better frame buffer grabs will be posted in a lossless format like .png.



Great and thanks, that was good to know.
Back to top
Display posts from previous:   
Post new topic   Reply to topic   Printer-friendly view    CurtPalme.com Forum Index -> CRT Projectors All times are GMT
Goto page Previous  1, 2
Page 2 of 2
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum